Methods for treating cancer with a recombinant MVA expressing HER-2

ABSTRACT

The invention relates to compositions, kits, and methods for cancer therapy using recombinant MVA viruses encoding a tumor-associated antigen, such as HER-2, particularly in combination with taxanes. The taxanes can be administered prior to, at the same time as, or after the recombinant MVA virus.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional application60/850,031, filed on Oct. 6, 2006, which is hereby incorporated byreference.

FIELD OF THE INVENTION

The invention relates to the treatment of cancers using MVA virusesencoding a tumor-associated antigen, particularly in combination withtaxanes.

BACKGROUND OF THE INVENTION

Modified Vaccinia Ankara (MVA) virus is related to vaccinia virus, amember of the genera Orthopoxvirus, in the family of Poxyiridae. MVA wasgenerated by 516 serial passages on chicken embryo fibroblasts of theAnkara strain of vaccinia virus (CVA) (for review see Mayr, A., et al.Infection 3, 6-14 (1975)). As a consequence of these long-term passages,the genome of the resulting MVA virus had about 31 kilobases of itsgenomic sequence deleted and, therefore, was described as highly hostcell restricted for replication to avian cells (Meyer, H. et al., J.Gen. Virol. 72, 1031-1038 (1991)). It was shown in a variety of animalmodels that the resulting MVA was significantly avirulent (Mayr, A. &Danner, K., Dev. Biol. Stand. 41: 225-34 (1978)). Additionally, this MVAstrain has been tested in clinical trials as a vaccine to immunizeagainst the human smallpox disease (Mayr et al., Zbl. Bakt. Hyg. I, Abt.Org. B 167, 375-390 (1987); Stickl et al., Dtsch. med. Wschr. 99,2386-2392 (1974)). These studies involved over 120,000 humans, includinghigh-risk patients, and proved that, compared to vaccinia-basedvaccines, MVA had diminished virulence or infectiousness, while itinduced a good specific immune response.

In the following decades, MVA was engineered for use as a viral vectorfor recombinant gene expression or as a recombinant vaccine (Sutter, G.et al., Vaccine 12: 1032-40 (1994)).

Even though Mayr et al. demonstrated during the 1970s that MVA is highlyattenuated and avirulent in humans and mammals, certain investigatorshave reported that MVA is not fully attenuated in mammalian and humancell lines since residual replication might occur in these cells.(Blanchard et al., J Gen Virol 79, 1159-1167 (1998); Carroll & Moss,Virology 238, 198-211 (1997); Altenberger, U.S. Pat. No. 5,185,146;Ambrosini et al., J Neurosci Res 55 (5), 569 (1999)). It is assumed thatthe results reported in these publications have been obtained withvarious known strains of MVA, since the viruses used essentially differin their properties, particularly in their growth behavior in variouscell lines. Such residual replication is undesirable for variousreasons, including safety concerns in connection with use in humans.

Strains of MVA having enhanced safety profiles for the development ofsafer products, such as vaccines or pharmaceuticals, have beendescribed. See U.S. Pat. Nos. 6,761,893 and 6,193,752. Such strains arecapable of reproductive replication in non-human cells and cell lines,especially in chicken embryo fibroblasts (CEF), but are not capable ofsignificant reproductive replication in certain human cell lines knownto permit replication with known vaccinia strains. Such cell linesinclude a human keratinocyte cell line, HaCat (Boukamp et al. J CellBiol 106 (3): 761-71 (1988)), a human cervix adenocarcinoma cell line,HeLa (ATCC No. CCL-2), a human embryo kidney cell line, 293 (ECACC No.85120602), and a human bone osteosarcoma cell line, 143B (ECACC No.91112502). Such strains are also not capable of significant reproductivereplication in vivo, for example, in certain mouse strains, such as thetransgenic mouse model AGR 129, which is severely immune-compromised andhighly susceptible to a replicating virus. See U.S. Pat. Nos. 6,761,893.One such MVA strain and its derivatives and recombinants, referred to as“MVA-BN,” have been described. See U.S. Pat. Nos. 6,761,893 and6,193,752.

MVA and MVA-BN have each been engineered for use as a viral vector forrecombinant gene expression or as a recombinant vaccine. See, e.g.,Sutter, G. et al., Vaccine 12: 1032-40 (1994), U.S. Pat. Nos. 6,761,893and 6,193,752.

Certain approaches to cancer immunotherapy have included vaccinationwith tumor-associated antigens. In certain instances, such approacheshave included use of a delivery system to promote host immune responsesto tumor-associated antigens. In certain instances, such deliverysystems have included recombinant viral vectors. See, e.g., Harrop etal., Front. Biosci. 11:804-817 (2006); Arlen et al., Semin. Oncol.32:549-555 (2005); Liu et al., Proc. Natl. Acad. Sci. USA 101 (suppl.2):14567-14571 (2004).

HER-2 is a tumor-associated antigen that is over-expressed in tumorcells of a number of cancer patients. Immunization with various HER-2polypeptides has been used to generate an immune response against tumorcells expressing this antigen. See, e.g., Renard et al., J. Immunology171:1588-1595 (2003); Mittendorf et al., Cancer 106:2309-2317 (2006).

Taxanes, such as paclitaxel and docetaxel, have been used aschemotherapies for cancer patients. Chemotherapy with taxanes has beencombined with different tumor vaccine treatments, resulting in a varietyof results. See, Chu et al., J. Immunotherapy 29: 367-380 (2006);Machiels et al., Cancer Res. 61: 3689-3697 (2001); Prell et al., CancerImmunol. Immunother. 55: 1285-1293 (2006); Arlen et al., Clinical BreastCancer 7: 176-179 (2006); and Arlen et al., Clinical Cancer Res. 12:1260-1269 (2006). The combination of cancer vaccines with chemotherapieshas been reviewed in Chong et al., Expert Opin. Phamacother. 6: 1-8(2005) and Emens et al., Endocrine-Related Cancer 12: 1-17 (2005).

Based on the above, a need in the art exists for reagents and methodsfor cancer therapy.

BRIEF SUMMARY OF THE INVENTION

The invention encompasses methods for treating cancer patients. In oneembodiment, the method comprises administering to the patient arecombinant MVA encoding a polypeptide comprising a HER-2 antigen andadministering to the patient a tumoricidal dose of a taxane. Thecombination treatment is superior to either treatment alone.

In a preferred embodiment, the MVA is MVA-BN.

In one embodiment, the HER-2 antigen comprises SEQ ID NO:2.

The recombinant MVA can be administered prior to the tumoricidal dose ofthe taxane, at the same time as the tumoricidal dose of the taxane, orafter the tumoricidal dose of the taxane.

In a preferred embodiment, the taxane is docetaxel. In another preferredembodiment, the taxane is paclitaxel. In one embodiment, the taxane isdocetaxel at a dose of 75-100 mg/m². In one embodiment, the taxane ispaclitaxel at a dose of 135-175 mg/m².

In one embodiment, the recombinant MVA is administered 1-26 weeks priorto the tumoricidal dose of the taxane. In one embodiment, therecombinant MVA is administered 1-3 weeks prior to the tumoricidal doseof the taxane.

In one embodiment, the recombinant MVA is administered 2-60 days afterthe tumoricidal dose of the taxane. In one embodiment, the recombinantMVA is administered 2-7 days after the tumoricidal dose of the taxane.

The invention further encompasses a kit for treating a cancer patientcontaining a recombinant MVA encoding a polypeptide comprising a HER-2antigen and instructions to administer the recombinant MVA prior to thetumoricidal dose of the taxane, at the same time as the tumoricidal doseof the taxane, or after the tumoricidal dose of the taxane.

The invention further encompasses a recombinant vaccinia virus encodinga polypeptide comprising a HER-2 antigen, wherein the HER-2 antigencomprises SEQ ID NO:2.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-B. Western blot analysis of mHER2 expression in primary CEFcells (A) or HeLa cells (B) following inoculation with MVA-BN-mHER2.Cell cultures were inoculated with MVA-BN or MVA-BN-mHER2 at thedilutions shown, or with TBS buffer, as described in Example 1. Cellswere harvested from the cultures 24 hours later and cell lysates wereprepared. Samples were electrophoresed through SDS-PAGE gels andelectroblotted onto nitrocellulose membranes. mHER2 protein was detectedby incubating with rabbit anti-HER-2 antiserum followed by detectionwith alkaline phosphatase-labeled anti-rabbit antibody and a chromogenicsubstrate as described in Example 1. Full length HER-2 protein and theextracellular domain of HER-2 are shown for reference. The arrows markthe position of protein detected with anti-HER-2 antiserum in lysatesfrom cell cultures.

FIG. 2A-C. Anti-HER-2 antibody responses in different mice strainstreated with MVA-BN-mHER2. C57BU6 (A) or BALB/c (B) mice (5 animals ineach group) were treated with 2E6 (♦), 1E7 (▪) and 5E7 (▴) TCID₅₀MVA-BN-mHER2 at day 1, 15 and 29 (indicated by arrows), as described inExample 2. Blood samples were collected and serial dilutions of pooledsera were analyzed for the presence of anti-HER-2 IgG by ELISA, asdescribed in Example 2. Titers or dilution factors at which signals twofold above background were detected are shown for different time points.(C) BALB/c (♦) and HER-2 transgenic BALB/c NeuT (▪) mice were treatedwith MVA-BN-mHER2 (1E7 TCID₅₀). Anti-HER-2 IgG titers were determined asin panels A and B.

FIG. 3A-C. Antigen specificity of MVA-BN-mHER2-induced anti-HER-2antibody responses. (A) Wells of a microtitration plate were coated withHER-2 ecd-Fc (black column), HER-3 ecd-Fc (gray column) and HER-4 ecd-Fc(white column), as described in Example 2. Antigens were then detectedby ELISA using a monoclonal anti-HER-2 antibody (HER-2 Ab; AB-5,Calbiochem), a monoclonal anti-human Ig Fc fragment antibody (Fc Ab;Southern Biotech) or a monoclonal isotype control antibody (Contr Ab).(B) and (C). ELISA assays were performed using sera from C57BL/6 (B) orBALB/c (C) mice treated with MVA-BN-mHER2 (5E7 TCID₅₀). Pre-treatmentsera were collected before the first treatment; post-treatment sera werecollected at day 42, two weeks after the last of three injections givenat two weeks intervals. Data shown are mean±standard deviation,indicated by the standard error bars.

FIG. 4A-D. HER-2-induced T-cell responses in different mice strainstreated with MVA-BN-mHER2. C57BL/6 (A and B) or BALB/c (C and D) mice (5animals in each group) were treated with TBS or 1E7 TCID₅₀ MVA-BN-mHER2as described in Example 3. Five days after the last treatment, spleenswere collected and cell suspensions were prepared for in vitrorestimulation. Secreted IFNγ was detected by standard ELISpot assay asdescribed in Example 3. A and C, incremental amounts of HER-2 ecd(filled symbols) or medium only (open symbols) were added to spleencells from mice treated with TBS (circles) or MVA-BN-mHER2 (diamonds). Band D, spleen cells from mice treated with TBS (empty bars) orMVA-BN-mHER2 (black bars) were restimulated with a HER-2 peptide or oneof the tetanus toxin peptides (TTp2 or TTp30) as described in Example 3.Data shown are mean±standard deviation, indicated by the standard errorbars.

FIG. 5. Analysis of tumor growth in mice pre-treated with MVA-BN-mHER2(Prophylactic setting). BALB/c mice (5 animals in each group) wereinjected subcutaneously with TBS (black triangles), MVA-BN-mHER2 (2E7TCID₅₀, black circles) or MVA-BN-mHER2 (2E6 TCID₅₀, open circles), asdescribed in Example 5. Six weeks after the last injection, mice werechallenged with TUBO (1E5) cells injected intradermally. Tumor growthwas determined twice weekly thereafter. Data shown are mean±standarddeviation, indicated by the standard error bars.

FIG. 6. Analysis of tumor growth in mice treated with MVA-BN-mHER2.BALB/c mice (9 animals in each group) were challenged with CT26-HER-2(5E5 cells injected intravenously) on day 1 and treatedintraperitoneally on day 4 with TBS, MVA-BN-mHER2 (5E7 TCID₅₀), orMVA-BN (5E7 TCID₅₀), as described in Example 5. Mice were sacrificed onday 14 and their lungs weighed. Tumor mass was calculated by subtractingthe average lung weight of naïve mice from the average lung weight oftumor challenged mice. Data shown are mean±standard deviation, indicatedby the standard error bars.

FIG. 7. Analysis of tumor growth in mice treated with MVA-BN-mHER2 orMVA-BN. BALB/c mice (9 animals in each group) were challenged withCT26-HER-2 (5E5 cells injected intravenously) on day 1 and treatedintraperitoneally the same day with TBS, MVA-BN (5E6 or 5E7 TCID₅₀) orMVA-BN-mHER2 (5E6 or 5E7 TCID₅₀), as described in Example 5. Mice weresacrificed on day 14 and their lungs weighed. Tumor mass was calculatedby subtracting the average lung weight of naive mice from the averagelung weight of tumor challenged mice. Data shown are mean±standarddeviation, indicated by the standard error bars.

FIG. 8 A-B. Anti-HER-2 antibody responses in mice co-treated withMVA-BN-mHER2 and docetaxel. C57BL/6 mice were treated subcutaneouslywith control (Tris Buffered Saline (TBS); I group of 5 animals) or with5E7 TCID₅₀ of MVA-BN-mHER2 (9 groups of 5 animals) at day 1, 22 and 43(q3 weeks×3). The effect of the chemotherapeutic agent docetaxel onanti-HER-2 antibody induction was evaluated by treating animals with thedrug at tumoricidal doses (33 mg/Kg) two days (day −2) (A) or one week(day −7) (B) prior to MVA-BN-mHER2 treatment. The drug was injected iveither once, twice (q3 weeks×2), three (q3 weeks×3) or four times (q3weeks×4) as described in Table 2.

FIG. 9 A-B. Analysis of tumor growth in mice pre-treated with docetaxeland MVA-BN-mHER2 (Prophylactic setting). The integrity of the immuneresponse induced by MVA-BN-mHER2 in mice treated with tumoricidal dosesof docetaxel was further evaluated by measuring the anti-tumor activityof MVA-BN-mHER2. Mice treated as described in legend of FIG. 8 werechallenged with MC38-HER-2 tumor cells at day 71 and tumor growth wasevaluated as described in legend of FIG. 5.

FIG. 10A-C. Analysis of tumor growth in mice co-treated with docetaxeland MVA-BN-mHER2. For each experimental subset A, B and C, C57BL/6 mice(40 animals) were challenged with MC38-HER-2 cells at day 1 then treatedsubcutaneously with either control (Tris Buffered Saline (TBS); 10animals treated 3 times), docetaxel alone (33 mg/Kg; 10 animals treatedonce), MVA-BN-mHER2 (5E7 TCID50; 10 animals treated twice) or docetaxel(1 treatment) and MVA-BN-mHER2 (two treatments) at varied times for eachexperimental subset as indicated in the Figure. Tumor growth wasevaluated twice a week until sacrifice at day 23.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

In one embodiment, the invention encompasses the use of recombinant MVAviruses for cancer therapy. The recombinant MVAs are generated byinsertion of heterologous sequences into an MVA virus. Examples of MVAvirus strains that are useful in the practice of the present inventionand that have been deposited in compliance with the requirements of theBudapest Treaty are strains MVA 572, deposited at the EuropeanCollection of Animal Cell Cultures (ECACC), Vaccine Research andProduction Laboratory, Public Health Laboratory Service, Centre forApplied Microbiology and Research, Porton Down, Salisbury, Wiltshire SP40JG, United Kingdom, with the deposition number ECACC 94012707 on Jan.27, 1994, and MVA 575, deposited under ECACC 00120707 on Dec. 7, 2000.MVA-BN, deposited on Aug. 30, 2000 at the European Collection of CellCultures (ECACC) under number V00083008, and its derivatives, areadditional exemplary strains.

Although MVA-BN is preferred for its higher safety (less replicationcompetent), all MVAs are suitable for this invention. According to anembodiment of the present invention, the MVA strain is MVA-BN and itsderivatives. A definition of MVA-BN and its derivatives is given inPCT/EP01/13628.

In certain embodiments, an MVA comprises at least one tumor-associatedantigen. In a preferred embodiment, the tumor-associated antigen is aHER-2 antigen. In one embodiment, the HER-2 antigen comprises thesequence of SEQ ID NO:2.

In further embodiments, the tumor-associated antigen is modified toinclude one or more foreign T_(H) epitopes. Such a cancerimmunotherapeutic agent is described herein in a non-limiting exampleand is referred to as “MVA-BN-mHER2.” As described herein, such cancerimmunotherapeutic agents, including, but not limited to MVA-BN-mHER2,are useful for the treatment of cancer. The invention allows for the useof such agents in prime/boost vaccination regimens of humans and othermammals, including immunocompromised patients; and inducing both humoraland cellular immune responses, such as inducing a Th1 immune response ina pre-existing Th2 environment.

The term “polypeptide” refers to a polymer of two or more amino acidsjoined to each other by peptide bonds or modified peptide bonds. Theamino acids may be naturally occurring as well as non-naturallyoccurring, or a chemical analogue of a naturally occurring amino acid.The term also refers to proteins, i.e. functional biomoleculescomprising at least one polypeptide; when comprising at least twopolypeptides, these may form complexes, be covalently linked, or may benon-covalently linked. The polypeptide(s) in a protein can beglycosylated and/or lipidated and/or comprise prosthetic groups.

In certain embodiments, the MVA is MVA-BN, deposited on Aug. 30, 2000,at the European Collection of Cell Cultures (ECACC) under numberV00083008, and described in U.S. Pat. Nos. 6,761,893 and 6,193,752. Asdescribed in those patent publications, MVA-BN does not reproductivelyreplicate in cell lines 293, 143B, HeLa and HaCat. In particular, MVA-BNexhibits an amplification ratio of 0.05 to 0.2 in the human embryokidney cell line 293. In the human bone osteosarcoma cell line 143B,MVA-BN exhibits an amplification ratio of 0.0 to 0.6. MVA-BN exhibits anamplification ratio of 0.04 to 0.8 in the human cervix adenocarcinomacell line HeLa, and 0.02 to 0.8 in the human keratinocyte cell lineHaCat. MVA-BN has an amplification ratio of 0.01 to 0.06 in Africangreen monkey kidney cells (CV 1: ATCC No. CCL-70).

The amplification ratio of MVA-BN is above 1 in chicken embryofibroblasts (CEF: primary cultures) as described in U.S. Pat. Nos.6,761,893 and 6,193,752. The virus can be easily propagated andamplified in CEF primary cultures with a ratio above 500.

In certain embodiments, a recombinant MVA is a derivative of MVA-BN.Such “derivatives” include viruses exhibiting essentially the samereplication characteristics as the deposited strain (ECACC No.V00083008), but exhibiting differences in one or more parts of itsgenome. Viruses having the same “replication characteristics” as thedeposited virus are viruses that replicate with similar amplificationratios as the deposited strain in CEF cells and the cell lines, HeLa,HaCat and 143B; and that show similar replication characteristics invivo, as determined, for example, in the AGR129 transgenic mouse model.

In certain embodiments, the MVA is a recombinant vaccinia virus thatcontains additional nucleotide sequences that are heterologous to thevaccinia virus. In certain such embodiments, the heterologous sequencescode for epitopes that induce a response by the immune system. Thus, incertain embodiments, the recombinant MVA is used to vaccinate againstthe proteins or agents comprising the epitope. In a preferredembodiment, the epitope is a tumor-associated antigen, preferably,HER-2. In one embodiment, the HER-2 antigen comprises the sequence ofSEQ ID NO:2.

In certain embodiments, a heterologous nucleic acid sequence is insertedinto a non-essential region of the virus genome. In certain of thoseembodiments, the heterologous nucleic acid sequence is inserted at anaturally occurring deletion site of the MVA genome as described inPCT/EP96/02926. Methods for inserting heterologous sequences into thepoxviral genome are known to a person skilled in the art.

In certain embodiments, pharmaceutical compositions comprise one or morepharmaceutically acceptable and/or approved carriers, additives,antibiotics, preservatives, adjuvants, diluents and/or stabilizers. Suchadditives include, for example, but not limited to, water, saline,glycerol, ethanol, wetting or emulsifying agents, and pH bufferingsubstances. Exemplary carriers are typically large, slowly metabolizedmolecules such as proteins, polysaccharides, polylactic acids,polyglycolic acids, polymeric amino acids, amino acid copolymers, lipidaggregates, or the like.

For the preparation of vaccines, the MVA can be converted into aphysiologically acceptable form. In certain embodiments, suchpreparation is based on experience in the preparation of poxvirusvaccines used for vaccination against smallpox, as described, forexample, in Stickl, H. et al., Dtsch. med. Wschr. 99, 2386-2392 (1974).

An exemplary preparation follows. Purified virus is stored at −80° C.with a titer of 5×10⁸ TCID₅₀/ml formulated in 10 mM Tris, 140 mM NaCl,pH 7.4. For the preparation of vaccine shots, e.g., 10²-10⁸ particles ofthe virus can be lyophilized in phosphate-buffered saline (PBS) in thepresence of 2% peptone and 1% human albumin in an ampoule, preferably aglass ampoule. Alternatively, the vaccine shots can be prepared bystepwise, freeze-drying of the virus in a formulation. In certainembodiments, the formulation contains additional additives such asmannitol, dextran, sugar, glycine, lactose, polyvinylpyrrolidone, orother additives, such as, including, but not limited to, antioxidants orinert gas, stabilizers or recombinant proteins (e.g. human serumalbumin) suitable for in vivo administration. The ampoule is then sealedand can be stored at a suitable temperature, for example, between 4° C.and room temperature for several months. However, as long as no needexists, the ampoule is stored preferably at temperatures below −20° C.

In various embodiments involving vaccination or therapy, thelyophilisate is dissolved in 0.1 to 0.5 ml of an aqueous solution,preferably physiological saline or Tris buffer, and administered eithersystemically or locally, i.e., by parenteral, subcutaneous, intravenous,intramuscular, intranasal, intradermal, or any other path ofadministration known to a skilled practitioner. Optimization of the modeof administration, dose, and number of administrations is within theskill and knowledge of one skilled in the art.

In certain embodiments, attenuated vaccinia virus strains are useful toinduce immune responses in immune-compromised animals, e.g., monkeys(CD4<400/μl of blood) infected with SIV, or immune-compromised humans.The term “immune-compromised” describes the status of the immune systemof an individual that exhibits only incomplete immune responses or has areduced efficiency in the defense against infectious agents.

Certain Exemplary Tumor-Associated Antigens

In certain embodiments, an immune response is produced in a subjectagainst a cell-associated polypeptide antigen. In certain suchembodiments, a cell-associated polypeptide antigen is a tumor-associatedantigen.

In certain embodiments, a cell-associated polypeptide antigen is aself-protein antigen other than a tumor-associated antigen, which isrelated to various pathological processes, or a viral antigen, orantigens derived from an intracellular parasite or bacterium. In certaininstances, such pathogen-associated antigens are often relatively poorimmunogens (e.g. antigens from mycobacteria such as Mycobacteriumtuberculosis and Mycobacterium leprae, but also from protozoans such asPlasmodium spp.).

Numerous tumor-associated antigens are known in the art. Exemplarytumor-associated antigens include, but are not limited to, 5 alphareductase, alpha-fetoprotein, AM-1, APC, April, BAGE, beta-catenin,Bcl12, bcr-ab1, CA-125, CASP-8/FLICE, Cathepsins, CD19, CD20, CD21,CD23, CD22, CD33 CD35, CD44, CD45, CD46, CD5, CD52, CD55, CD59, CDC27,CDK4, CEA, c-myc, Cox-2, DCC, DcR3, E6/E7, CGFR, EMBP, Dna78, farnesyltransferase, FGF8b, FGF8a, FLK-1/KDR, folic acid receptor, G250,GAGE-family, gastrin 17, gastrin-releasing hormone, GD2/GD3/GM2, GnRH,GnTV, GP1, gp100/Pmel17, gp-100-in4, gp15, gp75/TRP-1, hCG, heparanse,Her2/neu, HMTV, Hsp70, hTERT, IGFR1, IL-13R, iNOS, Ki67, KIAA0205,K-ras, H-ras, N-ras, KSA, LKLR-FUT, MAGE-family, mammaglobin, MAP17,melan-A/MART-1, mesothelin, MIC A/B, MT-MMPs, mucin, NY-ESO-1,osteonectin, p15, P170/MDR1, p53, p97/melanotransferrin, PAI-1, PDGF,uPA, PRAME, probasin, progenipoientin, PSA, PSM, RAGE-1, Rb, RCAS1,SART-1, SSX-family, STAT3, STn, TAG-72, TGF-alpha, TGF-beta,Thymosin-beta-15, TNF-alpha, TP1, TRP-2, tyrosinase, VEGF, ZAG, p16INK4,and glutathione-S-transferase.

One exemplary tumor-associated antigen is HER-2. HER-2 is a member ofthe epidermal growth factor receptor family (c-erbB) which consists offour different receptors to date: c-erbB-1 (EGFr), c-erbB-2 (HER-2,c-Neu), c-erbB-3 and c-erbB-4 (Salomon et al, 1995). C-erbB-3 andc-erbB-4 are less well characterized than EGFr and HER-2. HER-2 is anintegral membrane glycoprotein. The mature protein has a molecularweight of 185 kD with structural features that closely resemble the EGFrreceptor (Prigent et al, 1992). EGFr is also an integral membranereceptor consisting of one subunit. It has an apparent molecular weightof 170 kD and consists of a surface ligand-binding domain of 621 aminoacids, a single hydrophobic transmembrane domain of 23 amino acids, anda highly conserved cytoplasmic tyrosine kinase domain of 542 aminoacids. The protein is N-glycosylated (Prigent et al, 1994).

All proteins in this family are tyrosine kinases. Interaction with theligand leads to receptor dimerization, which increases the catalyticaction of the tyrosine kinase (Bernard. 1995, Chantry 1995). Theproteins within the family are able to homo- and heterodimerise, whichis important for their activity. The EGFr conveys growth promotingeffects and stimulates uptake of glucose and amino acids by cells(Prigent et al 1992). HER-2 also conveys growth promoting signals.

The epidermal growth factor receptor is expressed on normal tissues inlow amounts, but it is overexpressed in many types of cancers. EGFr isoverexpressed in breast cancers (Earp et al, 1993, Eppenberger 1994),gliomas (Schlegel et al, 1994), gastric cancer (Tkunaga et al, 1995),cutaneous squamous carcinoma (Fujii 1995), ovarian cancer (van Dam etal, 1994) and others. HER-2 is also expressed on few normal humantissues in low amount, most characteristically on secretory epithelia.Over-expression of HER-2 occurs in about 30% of breast, gastric,pancreatic, bladder and ovarian cancers.

The expression of these receptors varies depending on the degree ofdifferentiation of the tumors and the cancer type, e.g., in breastcancer, primary tumors overexpress both receptors; whereas in gastriccancer, the overexpression occurs at a later stage in metastatic tumours(Salomon et al, 1995). The number of overexpressed receptors oncarcinoma cells is greater than 10⁶/cell for several head and neckcancers, vulva, breast and ovarian cancer lines isolated from patients(Dean et al, 1994).

There are several reasons why the EGFr family of receptors constitutessuitable targets for tumor immunotherapy. First, they are overexpressedin many types of cancers, which should direct the immune responsetowards the tumor. Second, the tumors often express or overexpress theligands for this family of receptors and some are hypersensitive to theproliferative effects mediated by the ligands. Third, patients withtumors that overexpress growth factor receptors often have a poorprognosis. The overexpression has been closely linked with poorprognosis especially in breast cancer, lung cancer, and bladder cancerand can be associated with invasive/metastatic phenotypes, which arerather insensitive to conventional therapies (Eccles et al, 1994).

Modified Tumor-Associated Antigens

In certain embodiments, a cell-associated polypeptide antigen ismodified such that a CTL response is induced against a cell whichpresents epitopes derived from a polypeptide antigen on its surface,when presented in association with an MHC Class I molecule on thesurface of an APC. In certain such embodiments, at least one firstforeign T_(H) epitope, when presented, is associated with an MHC ClassII molecule on the surface of the APC. In certain such embodiments, acell-associated antigen is a tumor-associated antigen.

Exemplary APCs capable of presenting epitopes include dendritic cellsand macrophages. Additional exemplary APCs include any pino- orphagocytizing APC, which is capable of simultaneously presenting 1) CTLepitopes bound to MHC class I molecules and 2) T_(H) epitopes bound toMHC class II molecules.

In certain embodiments, modifications to HER-2 are made such that, afteradministration to a subject, polyclonal antibodies are elicited thatpredominantly react with HER-2. Such antibodies could attack andeliminate tumor cells as well as prevent metastatic cells fromdeveloping into metastases. The effector mechanism of this anti-tumoreffect would be mediated via complement and antibody dependent cellularcytotoxicity. In addition, the induced antibodies could also inhibitcancer cell growth through inhibition of growth factor dependentoligo-dimerisation and internalisation of the receptors. In certainembodiments, such modified HER-2 polypeptide antigens could induce CTLresponses directed against known and/or predicted HER-2 epitopesdisplayed by the tumor cells.

In certain embodiments, a modified HER-2 polypeptide antigen comprises aCTL epitope of the cell-associated polypeptide antigen and a variation,wherein the variation comprises at least one CTL epitope of a foreignT_(H) epitope. Certain such modified HER-2 polypeptide antigenscomprising at least one CTL epitope and a variation comprising at leastone CTL epitope of a foreign T_(H) epitope, and methods of producing thesame, are described in U.S. Pat. No. 7,005,498 and U.S. Patent Pub. Nos.2004/0141958 and 2006/0008465.

In certain embodiments, a foreign T_(H) epitope is a naturally-occurring“promiscuous” T-cell epitope. Such promiscuous T-cell epitopes areactive in a large proportion of individuals of an animal species or ananimal population. In certain embodiments, a vaccine comprises suchpromiscuous T-cell epitopes. In certain such embodiments, use ofpromiscuous T-cell epitopes reduces the need for a very large number ofdifferent CTL epitopes in the same vaccine. Exemplary promiscuous T-cellepitopes include, but are not limited to, epitopes from tetanus toxin,including but not limited to, the P2 and P30 epitopes (Panina-Bordignonet al., 1989), diphtheria toxin, Influenza virus hemagluttinin (HA), andP. falciparum CS antigen.

Additional promiscuous T-cell epitopes include peptides capable ofbinding a large proportion of HLA-DR molecules encoded by the differentHLA-DR. See, e.g., WO 98/23635 (Frazer I H et al., assigned to TheUniversity of Queensland); Southwood S et. al, 1998, J. Immunol. 160:3363 3373; Sinigaglia F et al., 1988, Nature 336: 778 780; Rammensee H Get al., 1995, Immunogenetics 41: 4 178 228; Chicz R M et al., 1993, J.Exp. Med. 178: 27 47; Hammer J et al., 1993, Cell 74: 197 203; and FalkK et al., 1994, Immunogenetics 39: 230 242. The latter reference alsodeals with HLA-DQ and -DP ligands. All epitopes listed in thesereferences are relevant as candidate natural epitopes as describedherein, as are epitopes which share common motifs with these.

In certain other embodiments, the promiscuous T-cell epitope is anartificial T-cell epitope which is capable of binding a large proportionof haplotypes. In certain such embodiments, the artificial T-cellepitope is a pan DR epitope peptide (“PADRE”) as described in WO95/07707 and in the corresponding paper Alexander J et al., 1994,Immunity 1: 751 761. mHER2

Various modified HER-2 polypeptide antigens and methods for producingthe same are described in U.S. Pat. No. 7,005,498 and U.S. Patent Pub.Nos. 2004/0141958 and 2006/0008465, which are hereby incorporated byreference. Those documents describe various modified HER-2 polypeptideantigens comprising promiscuous T-cell epitopes at different positionsin the HER-2 polypeptide.

The human HER-2 sequence can be divided into a number of domains basedsolely on the primary structure of the protein. Those domains are asfollows. The extracellular (receptor) domain extends from amino acids1-654 and contains several subdomains as follows: Domain I (N-terminaldomain of mature polypeptide) extends from amino acids 1-173; Domain II(Cysteine rich domain, 24 cysteine residues) extends from amino acids174-323; Domain III (ligand binding domain in the homologous EGFreceptor) extends from amino acids 324-483; and Domain IV (Cysteine richdomain, 20 cysteine residues) extends from amino acids 484-623. Thetransmembrane residues extend from amino acids 654-675. Theintracellular (Kinase) domain extends from amino acids 655-1235 andcontains the tyrosine kinase domain, which extends from amino acids655-1010 (core TK domain extends from 725-992); and the C-terminaldomain, which extends from amino acids 1011-1235.

Selection of sites in the amino acid sequence of HER-2 to be displacedby either the P2 or P30 human T helper epitopes is described in U.S.Pat. No. 7,005,498 and U.S. Patent Pub. Nos. 2004/0141958 and2006/0008465. To summarize, the following parameters were considered:

1. Known and predicted CTL epitopes;

2. Homology to related receptors (EGFR in particular);

3. Conservation of cysteine residues;

4. Predicted loop, α-helix and β-sheet structures;

5. Potential N-glycosylation sites;

6. Prediction of exposed and buried amino acid residues;

7. Domain organization.

The CTL epitopes appear to be clustered in domain I, domain III, the TMdomain and in two or three “hot spots” in the TK domain. As described inU.S. Pat. No. 7,005,498 and U.S. Patent Pub. Nos. 2004/0141958 and2006/0008465, these should be largely conserved.

Regions with a high degree of homology with other receptors are likelyto be structurally important for the “overall” tertiary structure ofHER-2, and hence for antibody recognition, whereas regions with lowhomology possibly can be exchanged with only local alterations of thestructure as the consequence.

Cysteine residues are often involved in intramolecular disulphide bridgeformation and are thus involved in the tertiary structure and should notbe changed. Regions predicted to form alpha-helix or beta-sheetstructures should be avoided as insertion points of foreign epitopes, asthese regions are thought to be involved in folding of the protein.

Potential N-glycosylation sites should be conserved if mannosylation ofthe protein is desired.

Regions predicted (by their hydrophobic properties) to be interior inthe molecule preferably should be conserved as these could be involvedin the folding. In contrast, solvent exposed regions could serve ascandidate positions for insertion of the model T_(H) epitopes P2 andP30.

Finally, the domain organization of the protein should be taken intoconsideration because of its relevance for protein structure andfunction.

As described in U.S. Pat. No. 7,005,498 and U.S. Patent Pub. Nos.2004/0141958 and 2006/0008465, the focus of the strategy has been toconserve the structure of the extracellular part of HER-2 as much aspossible, because this is the part of the protein which is relevant as atarget for neutralizing antibodies. By contrast, the intracellular partof native membrane bound HER-2 on the surface of cancer cells isinaccessible for the humoral immune system.

Various exemplary constructs using the P2 and P30 epitopes of tetanustoxin inserted in various domains of HER-2 are provided in U.S. Pat. No.7,005,498 and U.S. Patent Pub. Nos. 2004/0141958 and 2006/0008465. Oneexemplary modified HER-2 polypeptide antigen, referred to as “mHER2,”comprises the extracellular domains and nine amino acids of thetransmembrane domain; the P2 epitope inserted in Domain II between aminoacid residues 273 to 287 of the modified HER-2 polypeptide; and the P30epitope inserted in Domain IV between amino acid residues 655 to 675 ofthe modified HER-2 polypeptide.

Recombinant MVA-BN-mHER2

In a non-limiting embodiment, recombinant MVA comprising atumor-associated antigen, e.g., MVA-BN-mHER2, is constructed as follows.The initial virus stock is generated by recombination in cell cultureusing a cell type permissive for replication, e.g., CEF cells. Cells areboth inoculated with an attenuated vaccinia virus, e.g., MVA-BN, andtransfected with a recombination plasmid (e.g., pBN146) that encodes thetumor-associated antigen, e.g., mHER2, sequence and flanking regions ofthe virus genome. In one non-limiting embodiment, the plasmid pBN146contains sequences which are also present in MVA-BN (the 14 L and 15 Lopen reading frames). The mHER2 sequence is inserted between the MVA-BNsequences to allow for recombination into the MVA-BN viral genome. Incertain embodiments, the plasmid also contains a selection cassettecomprising one or more selection genes to allow for selection ofrecombinant constructs in CEF cells. In a preferred embodiment, therecombinant MVA encodes a polypeptide comprising SEQ ID NO:2.

Simultaneous infection and transfection of cultures allows homologousrecombination to occur between the viral genome and the recombinationplasmid. Insert-carrying virus is then isolated, characterized, andvirus stocks prepared. In certain embodiments, virus is passaged in CEFcell cultures in the absence of selection to allow for loss of theregion encoding the selection genes, gpt and EGFP.

Combination Therapy with Cytotoxic Agents

Cytotoxic agents display immunomodulatory activities at sub-tumoricidaldoses that could be beneficial for vaccine efficacy. However, attumoricidal doses (high doses), these agents could be detrimental tovaccine activities. It has now been demonstrated that human-equivalenttumoricidal doses of docetaxel given to mice during the course ofMVA-BN-mHER2 treatment did not affect the vaccine-induced anti-HER-2antibody titers. Moreover, treatment of mice with MVA-BN-mHER2 increasedtumor sensitivity to docetaxel in vivo. Hence, concurrent, prior, orsubsequent chemotherapy to MVA-BN-mHER2 treatment can be superior toeither treatment alone.

Patients with a cancer mediated by cells over-expressing thetumor-associated antigen HER-2 can be treated by the combination of MVAencoding a HER-2 antigen with a taxane. In a preferred embodiment, theMVA is MVA-BN. In a particularly preferred embodiment, the MVA encodes apolypeptide comprising SEQ ID NO:2.

The recombinant MVA encoding a HER-2 antigen can be administered eithersystemically or locally, i.e., by parenteral, subcutaneous, intravenous,intramuscular, intranasal, intradermal, or any other path ofadministration known to a skilled practitioner. In one embodiment,10⁵-10¹⁰ TCID₅₀ of the recombinant MVA are administered to the patient.Preferably, 10⁷-10¹⁰ TCID₅₀ of the recombinant MVA are administered tothe patient. More preferably, 10⁸-10¹⁰ TCID₅₀ of the recombinant MVA areadministered to the patient. Most preferably, 10⁸-10⁹ TCID₅₀ of therecombinant MVA are administered to the patient.

The cancer is preferably a breast cancer, a lung cancer, a gastriccancer, a pancreatic cancer, a bladder cancer, or an ovarian cancer. Ina preferred embodiment, the cancer is a metastatic breast cancer.

The cancer patient can be any mammal, including a mouse or rat.Preferably, the cancer patient is a primate, most preferably, a human.

In one embodiment, the taxane is docetaxel. In another embodiment, thetaxane is paclitaxel. The taxane is preferably administered at atumoricidal dose. A “tumoricidal dose” of docetaxel is at least 50mg/m². Preferably, the tumoricidal dose of docetaxel is 75-100 mg/m²,which corresponds to a dosage of approximately 25-33 mg/kg. A“tumoricidal dose” of paclitaxel is at least 90 mg/m². Preferably, thetumoricidal dose of paclitaxel is 135-175 mg/m². A “sub-tumoricidaldose” of a taxane is a dosage below the tumoricidal dosage. The taxanecan be administered by an means known to the skilled artisan, forexample, intravenously.

In one embodiment, the taxane and the MVA encoding a polypeptidecomprising a HER-2 antigen are administered at the same time. Thecombination treatment is superior to either treatment alone.

In one embodiment, the taxane is administered prior to the MVA encodinga polypeptide comprising a HER-2 antigen. In one embodiment, the MVAencoding a HER-2 antigen is administered within 6 months. In certainembodiments, the MVA encoding a HER-2 antigen is administered within 3months, within 2 months, or within 1 month after the taxane. In oneembodiment, the MVA encoding a HER-2 antigen is administered within 21days after the taxane. In one embodiment, the MVA encoding a HER-2antigen is administered within 14 days after the taxane. In oneembodiment, the MVA encoding a HER-2 antigen is administered within 7days after the taxane. Usually, the MVA encoding a HER-2 antigen isadministered at least 2 days after treatment with the taxane. Thecombination treatment is superior to either treatment alone.

In one embodiment, the taxane is administered after the MVA encoding apolypeptide comprising a HER-2 antigen. Usually, the MVA encoding aHER-2 antigen is administered at least 1 week prior to treatment withthe taxane. In one embodiment, the MVA encoding a HER-2 antigen isadministered less than 2 years prior to the taxane. In certainembodiments, the MVA encoding a HER-2 antigen is administered less than1 year, less than 6 months, or less than 3 months prior to the taxane.In one embodiment, the MVA encoding a HER-2 antigen is administered 1-26weeks prior to the taxane. In one embodiment, the MVA encoding a HER-2antigen is administered 1-9 weeks prior to the taxane. In oneembodiment, the MVA encoding a HER-2 antigen is administered 1-3 weeksprior to the taxane. The combination treatment is superior to eithertreatment alone.

In certain embodiments, the taxane is administered both prior to andafter the MVA encoding a HER-2 antigen. In other embodiments, the MVAencoding a HER-2 antigen is administered both prior to and after thetaxane. The administration of the MVA and the taxane can be a singleadministration or multiple administrations. For example, theadministrations can be 1, 2, 3, 4, 5, or 6 weeks apart.

The invention encompasses kits comprising recombinant MVA. Therecombinant MVA may be contained in a vial or container. Preferably, therecombinant MVA encodes a polypeptide comprising a HER-2 antigen. Invarious embodiments, kits for vaccination comprising a recombinant MVAfor the first vaccination (“priming”) in a first vial or container andfor a second vaccination (“boosting”) in a second via or container.

In one embodiment, the kit can contain a recombinant MVA andinstructions for the administration of the recombinant MVA prior toadministration of a tumoricidal dose of a taxane. The instructions caninstruct that the MVA is to be administered at any time point between 6months and 1 week prior to taxane administration. In preferredembodiments, the instructions instruct that the MVA is to beadministered at any time point between 3 months and 1 week, six weeksand 1 week, 1 month and 1 week, 3 weeks and 1 week, and 2 weeks and 1week prior to taxane administration. In one embodiment, the instructionscan instruct that the MVA is to be administered at any time pointbetween 1 week and 0 days prior to taxane administration.

The kit can also contain a recombinant MVA and instructions for theadministration of the recombinant MVA at the same time as administrationof a tumoricidal dose of a taxane.

The kit can also contain a recombinant MVA and instructions for theadministration of the recombinant MVA after administration of atumoricidal dose of a taxane. The instructions can instruct that the MVAis to be administered at any time point between 1 day and 6 months aftertaxane administration. In preferred embodiments, the instructionsinstruct that MVA is to be administered at any time point between 2 daysand 1 week, 2 days and 2 weeks, 2 days and 3 weeks, 2 days and 1 month,2 days and 2 months, and 2 days and 3 months, and 2 days and 6 monthsafter taxane administration. In one embodiment, the instructions caninstruct that the MVA is to be administered at any time point between 0and 2 days after taxane administration.

EXAMPLES Example 1 Construction of MVA-BN-mHER2 and Analysis of ProteinExpression in Infected Cells

Simultaneous infection and transfection of cultures allowed homologousrecombination to occur between the viral genome and the recombinationplasmid. Insert-carrying virus was isolated, characterized, and virusstocks were prepared.

Plasmid pBN146 contains sequences which are also present in MVA-BN (the14 L and 15 L open reading frames). The mHER2 sequence was insertedbetween the MVA-BN sequences to allow for recombination into the MVA-BNviral genome. Thus, a plasmid was constructed that contained the mHER2sequence downstream of a poxvirus promoter, specifically the cowpoxvirus A-type inclusion body gene promoter. The plasmid also contained aselection cassette comprising a synthetic vaccinia virus promoter (Ps),a drug resistance gene (guanine-xanthine phosphoribosyltransferase;Ecogpt), an internal ribosomal entry site (IRES), and the enhanced greenfluorescent protein (EGFP). Both selection genes (gpt and EGFP) wereencoded by a single bicistronic transcript.

The HER-2 sequence was modified by addition of nucleotides sequencesencoding tetanus toxin epitopes of p2 and p30 to increase the immuneresponse against it. After mHER2 was inserted into the MVA-BN genome,the virus “insert region” had the following structure:

ATI promoter-mHER2 sequence-Ps promoter-gpt-IRES-EGFP. The insert regionwas flanked by MVA-BN 14 L intergenic region sequences (F1 and F2) inthe bacterial recombination plasmid pBN146. The nucleotide sequence ofthe construct is shown below.

(SEQ ID NO: 1) AGTATGCATTTTTACGGATGGAGTCTCGGTCTAAAAACGGGAATGTACTATCTACGTACGAAACCCGCATCCGCTCCCATTCAATTCACATTGGACAAGGATAAAATAAAACCACTGGTGGTTTGCGATTCCGAAATCTGTACATCATGCAGTGGTTAAACAAATCTAGAACTAGTTTAATTAAGGAGCTGTTTTGAATAAAATTTTTTTATAATAAATCTAGAACTAGTGGATCCCCCGGGCTGCAGGA ATTCGATCTAGCCGCCACCATGGAGCTGGCGGCCTTGTGCCGCTGGGGGCTCCTCCTCGCCCTCTTGCCCCCCGGAGCCGCGAGCACCCAAGTGTGCACCGGCACAGACATGAAGCTGCGGCTCCCTGCCAGTCCCGAGACCCACCTGGACATGCTCCGCCACCTCTACCAGGGCTGCCAGGTGGTGCACGGAAACCTGGAACTCACCTACCTGCCCACCAATGCCAGCTTAAGTTTCCTGCAGGATATCCAGGAGGTGCAGGGCTACGTGCTCATCGCTCACAACCAAGTGAGGCAGGTCCCACTGCAGAGGCTGCGGATTGTGCGAGGCACCCAGCTCTTTGAGGACAACTATGCCCTGGCCGTGCTAGACAATGGAGACCCGCTGAACAATACCACCCCTGTCACAGGGGCCTCCCCAGGAGGCCTGCGGGAGCTGCAGCTTCGAAGCCTCACAGAGATCTTGAAAGGAGGGGTCTTGATCCAGCCGAACCCCCAGCTCTGCTACCAGGACACGATTTTGTGGAAGGACATCTTCCACAAGAACAACCAGCTGGCTCTCACACTGATAGACACCAACCGCTCTCGGGCCTGCCACCCCTGTTCTCCGATGTGTAAGGGCTCCCGCTGCTGGGGAGAGAGTTCTGAGCATTGTCAGAGCCTGACGCGCACTGTCTGTGCCGGTGGCTGTGCCCGCTGCAAGGGGCCACTGCCCACTGACTGCTGCCATGAGCAGTGTGCTGCCGGCTGCACGGGCCCCAAGCACTCTGACTGCCTGGCCTGCCTCCACTTCAACCACAGTGGCATCTGTGAGCTGCACTGCCCAGCCCTGGTCCAGTACATCAAAGCTAACTCCAAATTCATCGGTATCACCGAGCTGCGGTATACATTCGGCGCCAGCTGTGTGACTGCCTGTCCCTACAACTACCTTTCTACGGACGTGGGATCCTGCACCCTCGTCTGCCCCCTGCACAACCAAGAGGTGACAGOAGAGGATGGAACACAGCGGTGTGAGAAGTGCAGCAAGCCCTGTGCCCGAGTGTGCTATGGTCTGGGCATGGAGCACTTGCGAGAGGTGAGGGCAGTTACCAGTGCCAATATCCAGGAGTTTGCTGGCTGCAAGAAGATCTTTGGGAGCCTGGCATTTCTGCCGGAGAGCTTTGATGGGGACCCAGCCTCCAACACTGCCCCGCTCCAGCCAGAGCAGCTCCAAGTGTTTGAGACTCTGGAAGAGATCACAGGTTACCTATACATCTCAGCATGGCCGGACAGCCTGCCTGACCTCAGCGTCTTCCAGAACCTGCAAGTAATCCGGGGACGAATTCTGCACAATGGCGCCTACTCGCTGACCCTGCAAGGGCTGGGCATCAGCTGGCTGGGGCTGCGCTCACTGAGGGAACTGGGCAGTGGACTGGCCCTCATCCACCATAACACCCACCTCTGCTTCGTGCACACGGTGCCCTGGGACCAGCTCTTTCGGAACCCGCACCAAGCTCTGCTCCACACTGCCAACCGGCCAGAGGACGAGTGTGTGGGCGAGGGCCTGGCCTGCCACCAGCTGTGCGCCCGAGGGCACTGCTGGGGTCCAGGGCCCACCCAGTGTGTCAACTGCAGCCAGTTCCTTCGGGGCCAGGAGTGCGTGGAGGAATGCCGAGTACTGCAGGGGCTCCCCAGCGAGTATGTGAATGCCAGGCACTGTTTGCCGTGCCACCCTGAGTGTCAGCCCCAGAATGGCTCAGTGACCTGTTTTGGACCGGAGGCTGACCAGTGTGTGGCCTGTGCCCACTATAAGGACCCTCCCTTCTGCGTGGCCCGCTGCCCCAGCGGTGTGAAACCTGACCTCTCCTACATGCCCATCTGGAAGTTTCCAGATGAGGAGGGCGCATGCCAGCCTTGCCCCATCAACTGCACCCACTCCTGTGTGGACCTGGATGACAAGGGCTGCCCCGCCGAGCAGAGAGCCAGCCCTCTGACGTCCTTCAACAACTTCACCGTGAGCTTCTGGCTGCGCGTGCCCAAGGTGAGCGCCAGCCACCTGGAGATCGTCTCTGCGGTGGTTGGCATTCTGTAGAAGCTTGGTACCGAGCTCGGATCCACTAGTCCAGTGTGGTGGAATTCTGCAGATATCCAGCACAGTGGCGGCCATCAAGCTTATCGATACCGTCGACCTCGAGGGGGGGCCCGGTACCCAGTTAATTAAGGATCCCCCGGGCTGCAGGAATTCCATTTTTATTCTCAAATGAGATAAAGTGAAAATATATATCATATATACAAAGTA.

HER2 start and stop codons are indicated in bold. Flanking sequences areindicated in italics.

Translation of the encoded mHER2 polypeptide is shown below:

(SEQ ID NO: 2) MELAALCRWGLLLALLPPGAASTQVCTGTDMKLRLPASPETHLDMLRHLYQGCQVVQGNLELTYLPTNASLSFLQDIQEVQGYVLIAHNQVRQVPLQRLRIVRGTQLFEDNYALAVLDNGDPLNNTTPVTGASPGGLRELQLRSLTEILKGGVLIQRNPQLCYQDTILWKDIFHKNNQLALTLIDTNRSRACHPCSPMCKGSRCWGESSEDCQSLTRTVCAGGCARCKGPLPTDCCHEQCAAGCTGPKHSDCLACLHFNHSGICELHCPALVQYIKANSKFIGITELRYTFGASCVTACPYNYLSTDVGSCTLVCPLHNQEVTAEDGTQRCEKCSKPCARVCYGLGMEHLREVRAVTSANIQEFAGCKKIFGSLAFLPESEDGDPASNTAPLQPEQLQVFETLEEITGYLYISAWPDSLPDLSVFQNLQVIRGRILHNGAYSLTLQGLGISWLGLRSLRELGSGLALIHHNTHLCFVHTVPWDQLFRNPHQALLHTANRPEDECVGEGLACHQLCARGHCWGPGPTQCVNCSQFLRGQECVEECRVLQGLPREYVNARHCLPCHPECQPQNGSVTCFGPEADQCVACAHYKDPPFCVARCPSGVKPDLSYMPIWKFPDEEGACQPCPINCTHSCVDLDDKGCPAEQRASPLTSFNNFTVSFWLRVPKVSASHLEIVSAVVGIL.

The tetanus toxin epitopes of p2 and p30 sequences are indicated inbold.

CEF cultures were inoculated with MVA-BN and also transfected withpBN146 plasmid DNA. In turn, samples from these cell cultures wereinoculated into CEF cultures in medium containing selection drugs, andEGFP-expressing viral clones were isolated by plaque purification. Virusstocks which grew in the presence of the selection drugs and expressedEGFP were designated MVA-BN-mHER2. Generation of MVA-BN-mHER2 andpreparation of the virus stock involved twelve (12) sequential passages,including five (5) plaque purifications.

Next, MVA-BN-mHER2 was passaged in CEF cell cultures in the absence ofselection drugs. The absence of selection drugs allowed loss of theregion encoding the selection genes, gpt and EGFP and the associatedpromoter (the selection cassette) from the inserted sequence.Recombination resulting in loss of the selection cassette is mediated bythe F1 14 L region and a subsection of that region, the F1 repeat (F1rpt), which flank the selection cassette in plasmid pBN146. Theseduplicated sequences were included to mediate recombination that resultsin loss of the selection cassette, leaving only the mHER2 sequenceinserted in the 14 L intergenic region.

Plaque-purified virus lacking the selection cassette was prepared. Suchpreparation involved fifteen (15) passages including five (5) plaquepurifications.

The presence of the mHER2 sequence and absence of parental MVA-BN virusin MVA-BN-mHER2 stocks was confirmed by PCR analysis, and nested PCR wasused to verify the absence of the selection cassette (the gpt and EGFPgenes).

Expression of the mHER2 protein was demonstrated in cells inoculatedwith MVA-BN-mHER2 in vitro. Cultures of chicken embryo fibroblast (CEF)or HeLa cells were inoculated with MVA-BN-mHER2, or MVA-BN, at thedilutions shown, or with TBS buffer. Cells were harvested from thecultures 24 hours later and cell lysates were prepared. Samples wereapplied to SDS-PAGE gels (NuPAGE® Novex 4% to 12% Bis-Tris gels,Invitrogen), and electrophoresed in MOPS buffer under reducingconditions (dithiothreitol). Two Reference Standards obtained fromPharmexa A/S were included, namely HER-2 Standard, and HER-2extracellular domain standard (0.3 ug HER-2 ecd). Gels wereelectroblotted onto nitrocellulose membranes, which were incubated withrabbit anti-HER-2 antiserum (obtained from Pharmexa A/S). BoundHER-2-antibody was revealed with alkaline phosphatase-labeledanti-rabbit antibody and chromogenic substrate (Western Breeze™,Invitrogen).

The results are shown in FIG. 1. The arrows mark the position of proteindetected with anti-HER-2 antiserum in lysates from cell culturesinoculated with MVA-BN-mHER2. Antigen was detected in lysates from bothcell types inoculated with MVA-BN-mHER2 (denoted by arrows in FIG. 1)that was a similar size to the HER-2 protein reference standards. Noproteins were detected in lysates from cultures inoculated with MVA-BNor with Tris Buffer Saline (TBS) that were similar in size to HER-2protein reference standards.

These data demonstrate expression, in avian and human cells, of mHER2following inoculation of the cells with MVA-BN-mHER2. Therefore MVA-BNrepresents an effective delivery vehicle for the expression oftransgenic antigens like mHER2 in human cells.

Example 2 Induction of an Anti-HER-2 Immune Response in Mice Treatedwith MVA-BN-mHER2

Induction of an anti-HER-2 immune response following treatment withMVA-BN-mHER2 was evaluated in both BALB/c and C57BL/6 mice, two mousestrains with different immunological backgrounds or haplotypes.Induction of an anti-HER-2 immune response following treatment withMVA-BN-mHER2 was also evaluated in BALB/c NeuT mice, a transgenic HER-2mouse strain. In these studies, various doses of MVA-BN-mHER2 rangingfrom 2E6 to 5E7 TCID₅₀ were evaluated as described further below. Bloodsamples were collected one day prior to each treatment and at varioustimes during and after treatment as described below. Humoral responses(production of anti-HER-2 IgG) were analyzed by ELISA assay. Splenocyteswere collected after the final treatment and cellular responses wereanalyzed by ELISpot. Those studies are described in Example 3.

Mouse strains. Female BALB/c and C57BL/6 mice aged 8-10 weeks wereobtained from HSD. BALB/c NeuT mice were a generous gift from GuidoFormi. These mice express an activated HER-2/Neu oncogene under thecontrol of a chimeric mouse mammary tumor virus (MMTV) promoter. BALB/cNeuT females show no morphological abnormalities of the mammary glanduntil 3 weeks of age. They then progress through atypical hyperplasia toin situ lobular carcinoma. By 25 weeks of age, all 10 mammary glandsdisplay invasive carcinomas (Boggio et al, 1998, J. Exp. Med.). Allexperiments used five to ten mice per group.

Induction of Anti-HER-2 Antibody Responses in Mice Treated withMVA-BN-mHER2

BALB/c, C57BL/6, and BALB/c NeuT mice were injected subcutaneously withcontrol solution (Tris Buffered Saline (TBS)), or with 2E6, 1E7, or 5E7TCID₅₀ of MVA-BN-mHER2 at day 1, 15 and 29. Five animals were in each ofthose test treatment groups. Blood samples were collected at day 0, 14,28, 42 and 56. Sera from each of the five animals in each test groupwere pooled and analyzed for the presence of anti-HER-2 IgG using anELISA assay.

The ELISA assay was carried out as follows. ELISA plates were firstcoated with recombinant human ErbB2/Fc Chimera (R+D System, diluted incoating buffer (200 mM Na2CO3, pH 9.6)) at 2 μg/ml (50 μl/well) for onehour at room temperature. Plates were washed with PBS+0.05% Tween sixtimes using a plate washer (Wellwash AC, Thermo Electronics) andsubsequently blocked for 1 hour with PBS+0.05% Tween. Plates were washedsix times again. Mouse serum was diluted in PBS+0.05% Tween and added at50 μl/well. Plates were incubated for one hour at room temperature.Plates were then washed 6 times and sheep anti-mouse IgG-HRP secondaryantibody (Southern Biotech J3003-VI4513) was added (50 μl/well at 1:1000diluted in PBS+0.05% Tween). Plates were incubated for one hour at roomtemperature. Plates were washed six times and then 100 μl/well of TMBsubstrate was added to all wells. Plates were incubated for twentyminutes in the dark, then 100 μl of 0.5M H2SO4 was added to all wells.Absorbance at 450 nm in each well was determined using a plate reader(Thermo Electronics).

The results are shown in FIGS. 2A-C. FIGS. 2A and 2B show that ananti-HER-2 antibody response was detected in all MVA-BN-mHER2-treatedgroups in both C57BL/6 and BALB/c mice. In both strains, anti-HER-2antibody titers increased with multiple administrations of MVA-BN-mHER2and plateaued after treatment ceased. FIG. 2C shows that an anti-HER-2antibody response was also detected in HER-2 transgenic BALB/c NeuT micethat constitutively express HER-2. Thus, these data demonstrate thatMVA-BN-mHER2 is a potent immunogen that can overcome immune tolerance toHER-2, an attribute that can be useful for the treatment of cancerpatients.

Antigen Specificity of MVA-BN-mHER2-Induced Anti-HER-2 Antibody Response

The sera of MVA-BN-mHER2 treated mice were also evaluated by ELISA usingthe procedure described above. HER-2, HER-3, and HER-4 ecd-Fc chimericproteins were used as antigens coated onto the wells of a microtitrationplate. Antigens were detected using a monoclonal anti-HER-2 antibody(HER-2 Ab; AB-5, Calbiochem), a monoclonal anti-human Ig Fc fragmentantibody (Fc Ab; Southern Biotech), or a monoclonal isotype controlantibody (Contr Ab). The results are shown in FIG. 3. FIG. 3A shows theELISA controls: the monoclonal anti-HER-2 antibody specifically reactswith only HER-2 ecd-Fc coated wells, whereas the monoclonal anti-humanIg Fc fragment antibody reacts with all three chimeric proteins. FIGS.3B and 3C show that in both C57BL/6 and BALB/c mice treated withMVA-BN-mHER2, the sera only detected the HER-2 ecd-Fc chimera. Thesedata show that, in both mouse strains, the antibody response inducedafter MVA-BN-mHER2 treatment is highly specific to HER-2 and does notcross-react with certain other members of the Epidermal Growth Factorreceptor family, such as HER-3 and HER-4.

The induction of anti-HER-2 antibodies in MVA-BN-mHER2 treated mice wasalso evaluated by fluorescence-activated cell scan (FACS) analysis usinga murine cell line expressing human HER-2 (CT26-HER-2; described below).Sera of mice treated with MVA-BN-mHER2 contained antibodies that boundto cells expressing human HER-2, but not to their parental counterpartsthat do not express this receptor (data not shown).

In summary, these data demonstrate that treatment of mice withMVA-BN-mHER2 stimulates the formation of antibodies which are capable ofbinding to human HER-2 polypeptides as well as to human HER-2 expressedon the surface of cells.

Example 3 Induction of Anti-HER-2 T-Cell Responses

BALB/c and C57BL/6 mice (5 animals in each group) were injectedsubcutaneously with control (TBS) or 1E7 TCID₅₀ of MVA-BN-mHER2 at day1, 15, 29, and 43. Spleens were harvested from the animals at day 48 andcell suspensions from each test group were pooled for analysis. Theinduction of T-cell responses was evaluated by an ELISpot assay thatmeasured IFNγ production after in vitro antigen-specific restimulation.HER-2 ecd, a MHC Class I HER-2 peptide, and the two MHC Class IIT-helper peptides from tetanus toxin that are included in the mHER2sequence were used individually for restimulation. The Class I HER-2peptide had the amino acid sequence, TYLPTNASL (SEQ ID NO:3). The MHCClass II T-helper tetanus toxin peptide P2 had the amino acid sequence,QYIKANSKFIGITEL (SEQ ID NO:4) (labeled TTp2 in FIG. 4) and the MHC ClassII T-helper tetanus toxin peptide P30 had the amino acid sequence,FNNFTVSFWLRVPKVSASHLE (SEQ ID NO:5) (labeled TTp30 in FIG. 4).

THE ELISpot assay was performed as follows. Assay plates were preparedby pre-wetting membranes of Millipore Multiscreen 96-well filtrationplates by adding 15 μl 35% ethanol to each well. Ethanol was flicked outimmediately and the plates were washed twice with 200 μl/well PBS.Plates were coated with rat anti-mouse IFN-γ capture antibody (BDPharmingen, 551216, lot#34503) at 2 μg/ml (50 μl/well diluted in PBS)and incubated overnight at 4° C. Coating antibody was flicked out andplates were washed three times with PBS under sterile conditions. Plateswere blocked with 100 μl/well RPMI-10 (RPMI+110% FCS+β-mercaptoethanol)for at least 30 minutes at room temperature and subsequently washedtwice with PBS.

Effector cells were added in 50 μl of RPMI-10 (RPMI+10% FCS+2-ME 5×10-5M+1× Pen/Strep.) at indicated concentrations. HER-2 proteins, HER-2peptide, or tetanus toxin proteins and peptides were diluted in RPMI-10and added at appropriate dilutions (usually starting at 10 ug/ml forproteins and 25 μM for peptides, but varied throughout experiments) toeffector wells (50 μl/well). Plates were incubated at 37° C. in a CO₂incubator for approximately 18 hours.

Cells were flicked out of the wells and 100 μl/well dH₂O was added toall wells for 5 minutes at room temperature. Wells were washed threetimes with 100 μl/well dH₂O. Plates were then washed with a plate washer(Wellwash AC, Thermo Electron) six times, with PBS+0.05% Tween aswashing buffer.

50 μl/well anti-IFN-γ-biotin (Serotec, MCA1548B, batch#0803) at adilution of 1:5000 in PBS+5% FCS was added to all wells and incubatedfor one to two hours at room temperature. Plates were then washed usinga plate washer (Wellwash AC, Thermo Electron) for 6 cycles, withPBS+0.05% Tween as washing buffer. Then 50 μl/wellStreptavadin-AlkalinePhosphatase (BD Pharmingen, 554065, lot#46484) at adilution of 1:5000 in PBS+5% BSA was added to all wells and incubatedfor one hour at room temperature.

Plates were then washed again using a plate washer (Wellwash AC, ThermoElectron) for 6 cycles and subsequently developed in the dark by adding50 μl/well BCIP/NBT substrate for 15 minutes. Substrate was flicked outinto a sink and washed thoroughly with tap water. Backings of plateswere removed and plates were dried in a fume hood. Plates were scannedand read on an ImmunoSpot plate scanner using CellCount Pro software.

The results are shown in FIGS. 4A-D. FIGS. 4A and C show that adose-dependent T-cell response was detected in spleen cells of bothC57BL/6 (FIG. 4A) and BALB/c (FIG. 4C) strains of mice uponrestimulation with HER-2 ecd.

FIG. 4B (C57BL/6 mice) and FIG. 4D (BALB/c mice) show that IFNγproduction was also detected in this assay following incubation with aHER-2 MHC Class I peptide as well as both tetanus toxin MHC Class IIpeptides. This result indicates that both MHC Class I-specific CD8T-cells and MHC Class II-specific CD4 T-cells were induced in micetreated with MVA-BN-mHER2. These data confirm that the tetanus toxinpeptides in mHER2 act as T-helper epitopes and indicate thatMVA-BN-mHER2 treatment induces T-cells, including CD8 T-cells, thatreact with epitopes present in the native HER-2 protein.

In summary, these studies show that repeated treatment of mice withMVA-BN-mHER2 induces a broad antigen-specific adaptive immune responsethat includes antibodies as well as both CD4 and CD8 T-cell subtypes.Similar results were obtained in both C57BL/6 and BALB/c mice indicatingthat animals with different MHC haplotypes respond similarly. Asdiscussed above in Example 2, a specific antibody response was obtainedin HER-2-tolerant mice. Therefore, MVA-BN-mHER2 treatment has thepotential to mediate the elimination of self antigen-expressing tumorcells by multiple pathways and in varied MHC environments, which isdesirable for cancer treatment. Thus, treatment regimens employingmultiple injections of MVA-BN-mHER2 can be used in the treatment ofhuman cancer patients.

Example 4 Th1 Immune Modulation in MVA-BN-mHER2 Treated Mice

The data in the Examples above indicate that MVA-BN is an efficienttransgene delivery vehicle that also displays strong immunogenicproperties. It has previously been reported that MVA triggers a Th1adaptive immune responses that confers protection against smallpox (Earlet al., 2004; Wyatt et al., 2004) and also induces innate immuneresponses (Brutkiewicz et al., 1992; Dokun et al., 2001). Accordingly,the intrinsic immune properties of MVA-BN are potentially useful tomodulate immune responses to transgenes.

Examination of certain antibody subtypes produced followingadministration of immunogens is known to reveal certain characteristicsof the immune response. For example, IgG2a antibodies have been shown tobe prevalent in Th1 immune environments, whereas IgG1 antibodies areprevalent when a Th2 immune response is induced. Th1 immune environmentscomprise both humoral and cellular components of the immune response andthus, are conducive to long-lasting protective responses which may bedesirable in a cancer immunotherapeutic context. Th2 immuneenvironments, in contrast, comprise short-lived humoral components ofthe immune response, which are less desirable in a cancerimmunotherapeutic context. Thus, measuring the ratio of IgG2a to IgG1subtypes following administration of an immunogen in mice is a means ofassessing the Th1/Th2 characteristics of the immune response. Anincrease of the IgG2a/IgG1 ratio following administration of animmunogen is an indication of a shift toward a Th1 environment.Conversely, a lower ratio indicates a shift toward a Th2 response.

The ability of MVA-BN-mHER2 to modulate the immune response to HER-2 wasassessed by measuring the ratio of anti-HER-2 IgG2a to IgG1 antibodysubtypes produced following treatment of mice with various formulationscomprising HER-2 sequences. The IgG2a/IgG1 ratio of anti-HER-2antibodies induced after treatment of BALB/c mice with eitherMVA-BN-mHER2, mHER2 protein in Freund's adjuvant emulsion, or HER-2 (+)tumor cell lines was determined by ELISA using antibody-subtype-specificdetection antibodies. The ELISA assays were performed as describedabove, except with the substitution of the detection antibodies. Theresults are shown in Table 1 below.

The results show that the IgG2a/IgG1 ratio was significantly higher inmice treated with MVA-BN-mHER2 compared to mice treated with HER-2 inFreund's adjuvant or HER-2 (+) tumor cells. In addition, the resultsshow that the IgG2a/IgG1 ratio of antibody in serum from mice treatedwith HER-2 (+) tumor cell lines increased when these mice wereco-treated with MVA-BN-mHER2. That result indicates that even in a Th2environment, which resulted from administration of HER-2 (+) tumor celllines, the additional administration of MVA-BN-mHER2 effectively induceda Th1 response.

TABLE 1 IgG2a/IgG1 ratio of anti-HER-2 antibody responses induced byvarious formulations comprising HER-2 sequences. IgG2a/IgG1 FormulationMouse treatment ratio* MVA-BN-mHER2 3 subcutaneous injections at 2 weekintervals with doses 0.38 ± 0.09 ranging between 2E6 and 5E7 TCID₅₀HER-2 ECD in Freund's 3 subcutaneous injections at 2 week intervals with10 μg 0.08 ± 0.02 Adjuvant protein emulsified in CFA then IFA TUBO cells1E5 cells injected intradermally 0.03 ± 0.02 MC38-HER-2 1E5 cellsinjected intradermally 0.03 ± 0.02 TUBO cells + MVA-BN- 1E5 cellsinjected intradermally and 3 subcutaneous 0.69 ± 0.07 mHER2 injectionsat 1 week intervals with 5E7 TCID₅₀ MVA- BN-mHER2 (1st dose on same dayas cells) MC38-HER-2 + MVA-BN- 1E5 cells injected intradermally and 3subcutaneous  0.5 ± 0.07 mHER2 injections at 1 week intervals with 5E7TCID₅₀ MVA- BN-mHER2 (1st dose on same day as cells). *Values representthe mean ± standard deviation of at least two sets of duplicate wells.

In summary, these data demonstrate that the intrinsic immunogenicity ofMVA-BN, which is characterized by a strong bias toward Th1 immuneresponses, influences the immune response against HER-2 toward the Th1environment. This was true also when there was a Th2-biased anti-HER-2antibody response induced by tumor cells expressing HER-2. The potentimmune modulation property of MVA-BN described here is desirable in atherapeutic context since preexisting anti-HER-2 antibody responsesinduced by tumors have been reported in breast cancer patients. Thus,even if an undesirable Th2 response towards HER-2 already exists,treatment of patients with MVA-BN-mHER2 should refocus the immuneresponse towards a Th1 profile.

Example 5 Anti-Tumor Activity in Mice Treated with MVA-BN-mHER2

Prophylactic Treatment

The ability of MVA-BN-mHER2 to prevent tumor growth in a prophylacticcontext was evaluated using transplanted TUBO cells as a breast cancermodel in mice. TUBO cells are derived from a mammary gland carcinomathat developed in a BALB/c mouse transgenic for the transforming ratHER-2 (HER-2/neu) oncogene (Rovero et al, J. Immunol. 165, 5133-5142(2000)). Since the HER-2 sequence is highly conserved between rat andhuman, TUBO cells are used routinely to evaluate efficacy of vaccinescomprising either the rat or human homologues of HER-2 (Dela Cruz etal., Vaccine 23, 4793-4803 (2005)).

In this efficacy study, mice where immunized with MVA-BN-mHER2 asdescribed above, i.e., three times at 2-week intervals with either TBSor MVA-BN-mHER2 (2E6 or 5E7 TCID₅₀). Treated mice were then subjected totumor challenge by injecting 3E5 TUBO cells intradermally six weeksafter the last vaccine injection. Tumor growth at the injection site wasobserved twice weekly thereafter and the size of solid tumors under theskin was measured using calipers. Tumor volume (mm3) was calculatedusing the formula: V=(L×W2)/2, where L=length, W=width, (1 mm3=1 mg).The results presented in FIG. 5 show that the tumors in animalspretreated with MVA-BN-mHER2 were significantly smaller than the tumorsin control-treated mice.

The differences in tumor size were statistically-significant in micethat received MVA-BN-mHER2 at either dose, compared to the size oftumors in TBS-treated mice (p<0.005). At day 25, severalMVA-BN-mHER2-treated mice showed tumor stabilization, regression or eveneradication. Since mice were challenged with tumor cells six weeksfollowing the last MVA-BN-mHER2 treatment, these data show that theobserved inhibition of tumor growth was most likely mediated by therecall of a memory immune response induced by MVA-BN-mHER2administration.

In summary, these data show that treatment of mice with MVA-BN-mHER2induces an antigen-specific adaptive immune response and theestablishment of immune memory. When mice are subsequently challengedsubsequently with tumor cells expressing HER-2, the immune memory isrecalled and inhibits the growth of the tumor cells.

Therapeutic Treatment Suppression of Established Tumors by Treatmentwith MVA-BN-mHER2

The ability of MVA-BN-mHER2 to suppress established tumors was evaluatedin an experimental lung metastasis model using CT26 cells stablyexpressing human HER-2. CT26 is a chemically induced colorectalcarcinoma of BALB/c mice (Brattain et al., 1980). In this model,CT26-HER-2 cells are injected intravenously into BALB/c mice and tumorburden is assessed in the lungs where tumor nodules grow.

Mice were challenged with CT26-HER-2 (5E5) cells injected intravenouslyon day 1 and treated intraperitoneally on day 4 with a single injectionof TBS, MVA-BN (5E7 TCID₅₀) or MVA-BN-mHER2 (5E7 TCID₅₀). Mice were thensacrificed on day 14 and their lungs were weighed. Tumor mass wascalculated by subtracting the average lung weight of naïve mice (notchallenged with tumor cells) from the average lung weight oftumor-challenged mice.

The results are presented in FIG. 6. The results show that the tumorburden in mice treated with MVA-BN-mHER2 was significantly lower than incontrol mice (p<0.000001). In fact, sharply decreased lung weight wasobserved in all animals of the MVA-BN-mHER2 group compared to thecontrol group. In contrast, tumor burden was similar in mice of thecontrol and MVA-BN treated groups. In summary, treatment of mice withMVA-BN-mHER2 inhibits the growth of established HER-2 (+) tumors inmice.

Therapeutic Treatment Induction of Protective Innate Immunity afterTreatment with MVA-BN-mHER2 or MVA-BN

The ability of MVA-BN to contribute to the anti-tumor activity ofMVA-BN-mHER2 by triggering innate immunity was evaluated in the CT26tumor model described above. In this experiment, mice were treated witheither MVA-BN (5E6 or 5E7 TCID₅₀) or MVA-BN-mHER2 (5E6 or 5E7 TCID₅₀) onthe day of tumor challenge, a time at which the tumor burden is low.Tumor burden was assessed as described above in the lungs of challengedmice. The results are presented in FIG. 7. The results show that tumorgrowth inhibition (TGI) by treatment with MVA-BN (5E7 TCID₅₀) was >70%(p<0.0001). The anti-tumor activity of MVA-BN was dose-dependent sincetreatment with of MVA-BN (5E6 TCID₅₀) was less efficient (32% TGI;p=0.002) than treatment with 5E7 TCID₅₀. In contrast, mice treated withMVA-BN-mHER2 (either 5E6 or 5E7 TCID₅₀) displayed similar protection(>70% TGI; p<0.000001).

Taken together, the data shown in FIGS. 6 and 7 demonstrate that bothMVA-BN and MVA-BN-mHER2 have anti-tumor activity, yet the activity ofMVA-BN-mHER2 is superior. Indeed, treatment of mice in the pulmonarymetastases model on day 1 (FIG. 7) with MVA-BN-mHER2 (5E6 TCID₅₀) wasmore effective than treatment with the same dose of MVA-BN. In thismodel, treatment of mice on day 4 (FIG. 6) with MVA-BN-mHER2 alsosuppressed tumor growth whereas MVA-BN had no effect. Thus, theanti-tumor activity of MVA-BN observed in certain settings is mostlikely due to the stimulation of innate immunity. The superior activityof MVA-BN-mHER2 observed in all the experiments is likely due to thecombined stimulation of the innate immune system and induction of aspecific anti-HER-2 adaptive immune response.

Example 6 Combination Therapy with Cytotoxic Agents

C57BL/6 mice were treated subcutaneously with control (Tris BufferedSaline (TBS); I group of 5 animals) or with 5E7 TCID₅₀ of MVA-BN-mHER2(9 groups of 5 animals) at day 1, 22 and 43 (q3 weeks×3). The effect ofthe chemotherapeutic agent docetaxel on anti-HER-2 antibody inductionwas evaluated by treating animals with the drug at tumoricidal doses (33mg/Kg) one week (day −7) or two days (day −2) prior to MVA-BN-mHER2treatment. The drug was injected iv either once, twice (q3 weeks×2),three (q3 weeks×3) or four times (q3 weeks×4). The animal grouparrangement, administration regimen and schedule are summarized in Table2.

TABLE 2 Study Groups Treatment docetaxel Regimen (33 mg/Kg) Groups (n =5) Type Schedule Route Vaccine Regimen 1 None N/A N/A None 2 None N/AN/A MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 3 Doc d-2 X1 d-2 IVMVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 4 Doc d-2 X2 d-2 & d20 IVMVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 5 Doc d-2 X3 d-2, d20 & d41IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 6 Doc d-2 X4 d-2, d20,d41 & d62 IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 7 Doc d-8 X1d-7 IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 8 Doc d-8 X2 d-7 &d15 IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 9 Doc d-7 X3 d-7, d15& d36 IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43) 10 Doc d-7 X4 d-7,d15, d36 & d57 IV MVA-BN-mHER2 (5E7 TCID₅₀, SC @ d1, 22 & 43)

Blood samples were collected at day −9 (pre-bleed), 13 days post eachvaccine treatment (d14, 35, 56) and one week after the last drugtreatment (d70). Sera from each test group were pooled and analyzed byELISA using a commercially available HER-2 ecd-Fc chimeric protein asantigen coated onto the wells of a microtitration plate. This chimericprotein comprises the extracellular domain of native human HER-2 fusedto the Fc domain of a human immunoglobulin G. As shown in FIGS. 8A andB, an anti-HER-2 antibody response was detected in allMVA-BN-mHER2-treated groups and for each time point, the titers were notsignificantly different when mice were pretreated two or seven daysbefore vaccination with tumoricidal doses of docetaxel (33 mg/Kg).Moreover the antibody responses were not affected even when thedocetaxel treatment continued throughout the three-vaccination schedule.

The integrity of the immune response induced by MVA-BN-mHER2 in micetreated with tumoricidal doses of docetaxel was further evaluated bymeasuring the anti-tumor activity of MVA-BN-mHER2. Indeed, MVA-BN-mHER2was shown earlier (Example 5) to induce memory responses capable ofdelaying growth of tumors implanted post vaccination (prophylactic tumormodel). Mice of the study groups in Table 2 above were thereforechallenged with MC38-HER-2 tumor cells (Penichet et al., LaboratoryAnimal Science 49, 179-188 (1999)) at day 71 and tumor growth wasevaluated as described in Example 5. As shown FIGS. 9A and B, tumorgrowth was delayed in all mice groups treated with MVA-BN-mHER2.Pretreatment as well as concomitant treatment with docetaxel attumoricidal doses had no significant effect on tumor growth delay.Because this experiment was performed in a prophylactic setting, theanti-tumor effect measured was most likely mediated byMVA-BN-mHER2-induced anti-HER-2 immune responses while docetaxel had nodirect cytotoxic effect on the tumor. Indeed, the shortest time intervalbetween docetaxel treatment and tumor challenge was nine days (Group 6received its final docetaxel dose on day 62). Given the pharmacologicalproperties of chemotherapeutic agents, the drug concentration was likelytoo low at time of tumor implantation to be efficacious. Hence, the dataconfirmed that MVA-BN-mHER2 and docetaxel combined treatment is notdetrimental to the induction of protective immune response by thevaccine. This is true even when the chemotherapeutic agent was used attumoricidal doses at three weeks intervals, which mirrors standardtreatment regimen in humans.

The potential benefit provided by combination treatment of chemotherapyand immunotherapy was then evaluated in a therapeutic setting of themouse MC38-HER-2 tumor model. In this experiment, animals were dividedin three subsets (Subset A, B and C) where one chemotherapy treatmentwas given either before, during or following two immunotherapytreatments, respectively.

In subset A, C57BL/6 mice (40 animals) were challenged with MC38-HER-2cells at day 1 then treated subcutaneously with either control (TrisBuffered Saline (TBS); 10 animals treated on d1, 8 and 15), Docetaxelalone (33 mg/Kg; 10 animals treated on d1), MVA-BN-mHER2 (5E7 TCID50; 10animals treated on d8 and 15) or Docetaxel on day 1 then MVA-BN-mHER2 ond8 and 15. Tumor growth was evaluated twice a week until sacrifice atday 23. As shown in FIG. 10A, Docetaxel treatment on day 1 resulted in amodest and transient delay of tumor growth (statistically significantdifference was detected until day 19 only) whereas MVA-BN-mHER2treatment on day 8 and 15 had no effect on tumor growth. In contrast,the combined treatment of Docetaxel (d1) prior to MVA-BN-mHER2administration at d8 and 15 was highly efficient at inhibiting tumorgrowth throughout the study (p=0.001 at day 23).

For subset B, the experiment was performed with the same 4 animalgroups; however Docetaxel was given on d8 whereas MVA-BN-mHER2 wasadministered on day 1 and 15. It was previously determined thatDocetaxel had no effect on MC38-HER-2 growth once tumor size exceeds 50mg in weight, which is reached around day 8 for this model. As expected,Docetaxel treatment at day 8 had no effect on tumor growth (FIG. 10B)whereas two administration of MVA-BN-mHER2 at two weeks interval (on day1 and day 15) was highly efficient at inhibiting tumor growth (p=0.002at day 23). More importantly, this anti-tumor activity was notnegatively affected by high doses of Docetaxel administrated between thevaccine treatments (FIG. 10B).

For subset C, the experiment was also performed with the same 4 animalgroups; however Docetaxel was given on d15 whereas MVA-BN-mHER2 wasadministered on day 1 and 8. Like for Subset B, the tumors in all groupsexceeded the size limit beyond which Docetaxel is non-efficacious atreducing MC38-HER-2 growth at the time of chemotherapy treatment (day15). And as expected, FIG. 10C, shows that docetaxel had no effect ontumor growth when administered alone. Like in Subset A, vaccinetreatment consisting of two administrations of MVA-BN-mHER2 at one weekinterval was also suboptimal and had no effect on tumor growth as well.Surprisingly, the mean tumor size of the mice from MVA-BN-mHER2-treatedgroup that also received Docetaxel following the vaccine administrationwas significantly smaller (p=0.036 at day 23) than the mean of tumorsize of mice treated with MVA-BN-mHER2 only. This data shows thatMVA-BN-mHER2 treatment increases the sensitivity of MC38-HER2 toDocetaxel in vivo.

Overall the data show that MVA-BN-mHER2 and tumoricidal doses ofchemotherapeutic agents can be combined with no detrimental effects onthe potency of the vaccine. In fact, it was found that combining thesetwo therapies may be mutually beneficial since chemotherapypre-treatment increased vaccine efficacy whereas vaccine pre-treatmentincreased the sensitivity of tumor cells to chemotherapy. It istherefore anticipated that combined treatment of continued alternatedadministration of vaccine and chemotherapy also provide a new means togenerate more potent regimen for the treatment of cancer.

Example 7 Epitope/Antigen Spreading

Epitope/antigen spreading results from the induction of immune responsestriggered by exposure of epitopes/antigens from dying tumor cells.Vaccine-induced epitope/antigen spreading is highly advantageous formaximal anti-tumor activity. It was found that MVA-BN-mHER2 treatmentresults in epitope/antigen spreading since mice protected against HER-2+tumor resist a second challenge with the parental tumor that do notexpress HER-2. Hence, MVA-BN-mHER2 enables the triggering of a broadprotective immune response that can spread to tumor antigens other thanHER-2, which is a prerequisite to treat heterogeneous tumors and preventtumor escape.

Example 8 Spontaneous Tumors in NeuT Mice

A high titer and broad spectrum of antibody is required to delayspontaneous tumors arising in transgenic mice expressing rat HER-2/neu(NeuT mice) treated with heterologous HER-2 (e.g. Human HER-2). Vaccineformulation of heterologous HER-2 like naked DNA failed to delay tumorgrowth in this models whereas viral-based formulation displayedantitumor activity. It was found that MVA-BN-mHER2 delayed spontaneoustumor growth in NeuT even when treatment was started during the laterstages of tumor development. Hence, MVA-BN provides a superior antigenformulation for the induction of anti-tumor activity.

1. A method for treating a human cancer patient comprising: (a)administering to the patient a recombinant MVA expressing a polypeptidecomprising a HER-2 antigen; and (b) administering to the patient atumoricidal dose of a taxane, wherein administration of the MVA and thetaxane in combination is superior to either treatment alone to inhibittumor growth.
 2. The method of claim 1, wherein the MVA is MVA-BN. 3.The method of claim 1, wherein the HER-2 antigen comprises SEQ ID NO:2.4. The method of claim 1, wherein the recombinant MVA is administeredprior to the tumoricidal dose of the taxane.
 5. The method of claim 1,wherein the recombinant MVA is administered at the same time as thetumoricidal dose of the taxane.
 6. The method of claim 1, wherein therecombinant MVA is administered after the tumoricidal dose of thetaxane.
 7. The method of claim 4, wherein the taxane is docetaxel. 8.The method of claim 4, wherein the taxane is paclitaxel.
 9. The methodof claim 6, wherein the taxane is docetaxel.
 10. The method of claim 6,wherein the taxane is paclitaxel.
 11. The method of claim 7, wherein thetaxane is docetaxel at a dose of 75-100 mg/m².
 12. The method of claim8, wherein the taxane is paclitaxel at a dose of 135-175 mg/m².
 13. Themethod of claim 9, wherein the taxane is docetaxel at a dose of 75-100mg/m².
 14. The method of claim 10, wherein the taxane is paclitaxel at adose of 135-175 mg/m².
 15. The method of claim 4, wherein therecombinant MVA is administered 1-26 weeks prior to the tumoricidal doseof the taxane.
 16. The method of claim 4, wherein the recombinant MVA isadministered 1-3 weeks prior to the tumoricidal dose of the taxane. 17.The method of claim 6, wherein the recombinant MVA is administered 2-60days after the tumoricidal dose of the taxane.
 18. The method of claim6, wherein the recombinant MVA is administered 2-7 days after thetumoricidal dose of the taxane.
 19. A kit for treating a cancer patientcomprising: (a) a recombinant MVA expressing a polypeptide comprising aHER-2 antigen; and (b) instructions to administer the recombinant MVAprior to treatment with a tumoricidal dose of a taxane, whereinadministration of the MVA and the taxane in combination is superior toeither treatment alone to inhibit tumor growth.
 20. A kit for treating acancer patient comprising: (a) a recombinant MVA expressing apolypeptide comprising a HER-2 antigen; and (b) instructions toadminister the recombinant MVA at the same time as treatment with atumoricidal dose of a taxane, wherein administration of the MVA and thetaxane in combination is superior to either treatment alone to inhibittumor growth.
 21. A kit for treating a cancer patient comprising: (a) arecombinant MVA expressing a polypeptide comprising a HER-2 antigen; and(b) instructions to administer the recombinant MVA after treatment witha tumoricidal dose of a taxane, wherein administration of the MVA andthe taxane in combination is superior to either treatment alone toinhibit tumor growth.
 22. The kit of claim 19, wherein the HER-2 antigencomprises SEQ ID NO:2.
 23. The kit of claim 20, wherein the HER-2antigen comprises SEQ ID NO:2.
 24. The kit of claim 21, wherein theHER-2 antigen comprises SEQ ID NO:2.
 25. A recombinant vaccinia virusexpressing a polypeptide comprising a HER-2 antigen, wherein the HER-2antigen comprises SEQ ID NO:2, and wherein administration of the MVA anda tumoricidal dose of a taxane in combination is superior to eithertreatment alone to inhibit tumor growth.